PURPOSE: The user can be identified as being authorized to access an encrypted Data Base Library (DBL) with the PERMIT DBL command.
These keys are checked against encrypted DBL’s as they are accessed. A two hash code system is used so that the actual cipher keys are not available except when the cipher key is given at run time. The first hash code is stored in the DBL and is used to check that a valid cipher key was entered for that object in the PERMIT DBL command. The second hash code is computed when the cipher key is entered and is used to cipher and decipher the data. The second hash code cannot be derived from the first, but requires the cipher key to compute it so it is only available at run time.
A DBL cipher key must be specified with the DBL name so that it can be associated with a given DBL since it is possible to have cross-DBL operations referencing several DBL’s in a given Command Module (CM) or Process Module (PM).
Up to 10 encrypted DBL’s can be accessed at one time through PERMIT DBL commands. ACCENT R maintains a table of DBL cipher keys with 10 entries. When entering the 11th cipher key, the oldest entry in the table is overwritten.
This command must be executed before the USE DBL command
PERMIT DBL dbl_name KEY IS {cipher_key; TERMINAL}
| dbl_name | is the name of the DBL that is being accessed. |
| cipher_key; | is the cipher key associated with the DBL. |
| TERMINAL | prompts the user for the cipher key from the screen. The cipher key will not echo on the screen when it is entered. |
Example
*PERMIT DBL BOOKS KEY IS TERMINAL<CR>NOTES: Several encrypted DBL’s can be accessed at the same time. Before giving the command or PM statement that accesses the DBL, enter the cipher key for the DBL.